By Borys KitAs film backstories go, this one is fairly serpentine. This month, New Line Cinema's "Snakes on a Plane," which wrapped principal photography in September in Vancouver, went back before the cameras for five days of additional shooting at the Lot in Los Angeles.

In this case, it wasn't the usual reshoot, hastily assembled to fix a nagging story problem. Instead, the studio decided to create new scenes that would take the movie from PG-13 into R-rated territory.

The second round of filming also came about because of intense and growing fan interest in the movie, which was directed by David R. Ellis and is not scheduled to be released until Aug. 18.

"Snakes" stars Samuel L. Jackson as an FBI agent who has to fight a planeload of snakes unleashed by an assassin bent on killing a witness in protective custody. Sight unseen, the movie has grown from something of a joke into a phenomenon slithering untamed throughout the Internet.

As a movie whose fan base has grown spontaneously and organically, "Snakes" is relatively rare.

Intense fan reaction to movies most often is associated with titles that have established themselves in other media, such as comic book movies or fantasy novels, before making their way to the screen. Or it becomes attached to surprise hits, like the original "Star Wars," that develop massive cult followings once they are released.

But original movies that develop a big prerelease following are uncommon. Artisan Entertainment pulled off that trick in 1999 with its viral Internet campaign for "The Blair Witch Project," but that success has not been easily duplicated.

"Snakes," based an original script by John Heffernan (with rewrites by David Louca, Sheldon Turner, Sebastian Gutierrez and Chris Morgan) barely has an official Web site at the moment. But the movie, produced by Craig Berenson, Don Granger and Gary Levinsohn, already is the talk of a certain segment of the Net without any real prodding on the part of New Line.

It all started with the provocative and buzzworthy, if also reductive, title. New Line picked up the script in turnaround from Paramount Pictures in March 2003 -- in the wake of Sept. 11, terror-on-a-plane movies had fallen out of favor. And even within New Line, there were skeptics who viewed "Snakes on a Plane" as nothing but a simple programr with a "stupid title."

After Jackson came on board as the star, the title was upgraded to the more generic "Pacific Air Flight 121." The studio said it was a temporary moniker being used for "casting purposes." Executives were searching for something that was more thriller-like and less campy. According to sources, Jackson's camp also was in favor of a title change.

"Who wants to be in a movie called 'Snakes on a Plane'?" asked one talent agent at the time, seeming to echo the studio's concerns.

But once production began, a funny thing happened. Movie fans began noticing the black sheep of the New Line slate. They seized upon the title and started spontaneously creating fan sites, blogs, T-shirts, poems, fiction and songs. The title itself, sometimes abbreviated as "SoaP," has emerged as Internet-speak for fatalistic sentiments that range from c'est la vie to "shit happens."

"The title is so clear and so straightforward," said Brian Finkelstein, a Washington, D.C., native who created the blog Snakesonablog.com and who hopes to score tickets to the movie's premiere. "You know exactly what you're going to get."

Like Harry Potter, whose first suggestion that he's got magic on his hands comes when he discovers he can talk to snakes in their language , New Line got the message. Deciding that so many anonymous fans couldn't be wrong, the studio decided to revert to the movie's original title.

Jackson publicly endorsed the move. "That's the only reason I took the job: I read the title," Jackson told entertainment site Collider.com. He added, "You either want to see that, or you don't."

New Line execs, concerned that it is too early to discuss the movie, declined comment. But sources now insist the studio never abandoned the "Snakes" title in the first place and that "Pacific Air" was just an internal working title.

In any event, "Snakes"-ophiles already were hard at work. Chris Rohan of Bethesda, Md., created an elaborate, R-rated audio trailer that lovingly mocks the title and movie. "It's a genius title," Rohan said. "It's so stupid it's great. It invites satire, but it's something you just love. It's something I can't explain. You either get it or you don't."

The audio bit uses a Jackson sound-alike shouting, "I want these motherfucking snakes off the motherfucking plane!" Soon, the growing legion of fans added their voices as they demanded that that phrase also appear in the movie.

Apparently, the studio got the hint. When Ellis assembled Jackson and others for the recent shoot, the filmmakers added more gore, more death, more nudity, more snakes and more death scenes. And they shot a scene where Jackson does utter the line that fans have demanded.

Those involved with the film said the reshoots weren't prompted by fans but rather by the existing footage that already was a hairline into R territory. Within the studio, the thinking was, "We're already going to get an R, why not go all the way?" But the filmmakers do concede that the Jackson line will be in the movie for the sake of the fans.

Meanwhile, the phenomenon keeps growing.

David Coin, a Maryland-based friend of Rohan, pitched in by creating a "Snakes" song and is working on a second.

New Line, in turn, is reaching out to the fans. In response to populist "Snakes" songs already created, the studio has just teamed up with social-networking site TagWorld.com to launch a contest that will allow one lucky winner's song to be featured in the movie.

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